Ball for ball game

ABSTRACT

An object of the present invention is to provide a ball for ball games which has equivalent or increased cushioning property to a ball which has seams without providing inflatable raised seams with cushion layers under outer covering. A ball for ball games in the present invention includes a bladder made of rubber or elastomer, and an foamed layer covered an outside of the bladder, in which a skin layer is provided on each surface which is divided to sectionalize the surface of the foamed layer, a partition of the foamed layer has lower foamed property than each surface which is divided to sectionalize the surface.

TECHNICAL FIELD

The present invention relates to ball for ball game.

BACKGROUND ART

Basketballs have been standardized into an eight-panel outer surface design having raised seams exposed between the edges of exterior skin panels. Basketballs generally consist of rubber bladder surrounded by a thread-winding layer.

The arrangement of bladder, thread-winding portion, and a rubber layer are placed in a mold and cured to make the “carcass” of the ball.

During the carcass molding process, raised ridges or seams are molded from the rubber layer. Individual panel section of leather is bonded to the rubber layer in a region between raised seams. After attachment of the panels the ball is completed in a finishing mold.

Basketballs have been made in the above manner. The thread-winding layer around the surface limits expansion of the bladder and assists it in retaining a spherical shape after inflation to a desired pressure. It also prevents the air pressure within the bladder from being fully transferred to the outer covering defined by the panel portions and seams.

The outer covering provides durability and protection. It is common to use synthetic materials to make the panel portions. However, the highest quality balls use top-grain leather.

One ball design developed in the past by the A. G. Spalding Co. (“Spalding design”) includes a porous sponge layer positioned between what is characterized as an “inner carcass” and outer skin. This design is illustrated in U.S. Pat. No. 3,119,618.

The Spalding design lacks the rubber layer described above for creating raised seams on the ball described in U.S. Pat. No. 3,119,618.

On the one hand, the invention disclosed in U.S. Pat. No. 5,636,835 is inflatable, raised seam game ball having a layer of padding underneath the outer covering.

The carcass of the ball is preferably made in the following manner.

Surrounding a spherical rubber bladder by a thread-winding layer;

After the thread-winding layer is wound around the bladder, providing a layer of foamable rubber in a prefoamed condition around the thread-winding layer and covering it completely;

Applying a foaming agent to the foamable rubber. Positioning narrow strips of seam material (high density black rubber) over the foamable rubber at the locations where it is desired to create raised seams;

Placing this arrangement in a carcass mold where it is cured under temperature in a conventional method;

During the molding process, expanding the foamable layer into a porous sponge rubber layer. At the same time, molding the seam strips into raised seams;

As a result, removing from the mold, it becomes raised black seams partially covering the surface of the sponge layer and the sponge rubber layer covering thread-winding layer.

As with typical leather game balls, the boundaries of the exterior skin panels are defined by the raised seams. Each panel is bonded in a region between seams.

A basketball illustrated in U.S. Pat. No. 5,636,835 has an inner carcass structure, or inner carcass portion, consisting, in combination, of a rubber bladder 12 and a thread-winding layer 14 (see, for example, FIG. 1).

The thread-winding layer 14 surrounds the bladder 12, and the porous sponge 16 surrounds the thread-winding layer 14. A plurality of skin panels 18 and a plurality of seams 20 are bonded to the porous layer 16. Generally, the ball 10 has a total of eight panels separated by seams, which is typical to basketballs.

Each seam 20 is made of a narrow strip of seam material preferably a high density rubber. A raised central portion 22 of the seam material 20 fills the space between the outer edges 24 and 26 of two adjacent skin panels 28, 30 as well as conventional basketballs.

However, narrow flanges portions 32, 34 of the seam material 20 extend outwardly, in opposite directions, a definite distance from the raised portion 22 which is different from conventional basketballs.

The flange portions 32, 34 underlie the overlapping panel edges 24, 26 and are also sandwiched between the panel edges and underlying sponge layer 16. In other areas, the skin panels 18 a, 18 b are bonded directly to the sponge layer 16, as shown by numerals 36, 38.

A basketball illustrated in U.S. Pat. No. 3,119,618 has no rubber layer for making a raised seam. However, in stead of providing raised seam, it is well known to provide a protrusion in a sponge layer (for example, Japanese Unexamined Utility Model Publication No. 157253/1976).

Referring to FIGS. 2 and 3, a basketball in illustrated in Japanese Unexamined Utility Model Publication No. 157253/1976 includes a bladder 51 made of butyl rubber, thread-winding layer of nylon thread 52 wound uniformly around the outside of the bladder 51, and vulcanized rubber 53 covering the outside of thread-winding layer 52. The vulcanized rubber 53 includes bubbles, and provides very soft touch.

The carcass 54 is constructed by the bladder 51, thread-winding layer 52, and vulcanized rubber layer 53. Numeral 55 indicates a partition formed on the carcass 54. The surface of carcass 54 is sectionalized into a shape of carapace of a turtle with 8 sections, 12 sections, 18 sections, or 32 sections. Numeral 56 indicates a surface sectionalizing and dividing on the surface surrounded by the partition 55. Numeral 57 indicates a spherical surface of the surface 56 in a shape of sphere sectionalizing and dividing on the surface. Numeral 58 indicates a peripheral portion of surface 56 which is divided to sectionalize the surface with a shape of arc on its cross section. The peripheral portion 58 smoothly bonds to the spherical surface 57. Numeral 59 is a side of partition, making an acute angle with the peripheral portion 58 described above. Numeral 60 is leather which is attached to the surface 56 which is divided to sectionalize the surface, and thin as compared to conventional leather. The periphery of a back surface of leather 60 is not skived. The cross section of attached leather 60 is directly bonded to the center of side 59 of the partition 55. Thus, when using ball, the cross sectional surface of the attached leather 60 is not peeled from peripheral edge of leather 60 by catching fingers on the surface of the ball. As leather 60 is thin, it is readily attached. As the peripheral edge portion 58 has a cross section with a shape of circular arc and is bonded smoothly to the spherical surface 57, unevenness does not occur on the surface of the attached leather 60 and very good handling in use is provided.

A basketball illustrated in Japanese Unexamined Utility Model Publication No. 157253/1976 constructs the peripheral edge 58 of each surface 56 which is divided to sectionalize the surface in a shape of arc with the smooth seam by a much smaller radius than a radius of the ball on an arbitrary virtual plane which penetrates into the center of the ball. The side face 59 of partition 55 is formed, in order that virtual straight line drawn on the side face 59 of partition 55 penetrates into approximately the center of the ball. The leather 60, which has a uniform thickness without skiving, is applied on the surface 56 which is divided to sectionalize the surface.

DISCLOSURE OF INVENTION

The present invention aims to provide a ball for ball game which has equal or increased cushioning property to a ball which has seams, without providing inflatable raised seams with cushion layers under an outer covering, as disclosed in U.S. Pat. No. 5,636,835.

The ball for ball game of the first Embodiment in the present invention comprising:

a bladder made of rubber or elastomer; and

a foamed layer covering an outside of the bladder;

wherein a skin layer is provided on each surface which is divided to sectionalize the surface of the foamed layer, and a partition on the foamed layer has lower foamed property than each surface which is divided to sectionalize the surface.

The ball for ball game of the second Embodiment in the present invention comprising:

a bladder made of rubber or elastomer;

a reinforcement layer covering an outside of the bladder; and

a foamed layer covering an outside of the reinforcement layer;

wherein a peripheral edge of each surface of the foamed layer which is divided to sectionalize the surface is formed in a shape of arc with a smooth seam, a skin layer is provided on each surface of the foamed layer which is divided to sectionalize the surface, and a partition of the foamed layer has lower foamed property than each surface which is divided to sectionalize the surface.

The number of cells in a partition of the foamed layer is also preferable to be less than the number of cells in each surface of the foamed layer which is divided to sectionalize the surface.

It is preferable a foamed property in partition of the foamed layer decreases gradually as an interval from each surface which is divided to sectionalize the surface increases.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional explanation view showing one example of a ball according to a conventional art;

FIG. 2 is a cross sectional explanation view showing another example of a ball according to a conventional art;

FIG. 3 is an enlarged view of a substantial portion of a ball in FIG. 2;

FIGS. 4(a) and 4(b) are cross sectional explanation views showing processes for manufacturing method of a vulcanized rubber layer which constructs a ball of the present invention;

FIGS. 5(a) and 5(b) are cross sectional explanation views showing a vulcanized rubber layer and a partition which construct a ball of the present invention; and

FIG. 6 is a graph showing a comparison of the performance between a ball according to examples of the present invention and a ball of comparative examples.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to attached drawings, a ball for ballgame (hereinafter referred to as “ball”) is explained in detail as the followings.

FIGS. 4(a) and 4(b) are cross sectional explanation views showing processes for manufacturing method of a ball of the present invention, FIGS. 5(a) and 5(b) are cross sectional explanation views of a vulcanized rubber layer which constructs a ball of the present invention, FIG. 6 is a graph showing a comparison of the performance between a ball relating to examples of the present invention and a ball of comparative examples.

As a ball of the present invention basically has the same construction as a ball illustrated in Japanese Unexamined Utility Model Publication No. 157253/1976, the same constructional portions as Japanese Unexamined Utility Model Publication No. 157253/1976 are explained with the same numerals.

Referring to FIGS. 4(a) to 6, a ball of the present Embodiment comprises a bladder 51 made of rubber, reinforcement layer 52 (thread-winding layer, in which a thread is uniformly wound) provided on outside of bladder 51, vulcanized rubber layer 53 covering the thread-winding layer obtained by vulcanizing unvulcanized rubber having foamable property. The carcass 54 comprises the bladder 51, thread-winding layer 52, and vulcanized rubber layer 53. It is well known that a thread-winding layer, cotton cloth and things which are obvious to persons skilled in the art as reinforcement layers of a ball for ball game are included. The bladder 51 described later which has reinforcement function in itself is known to persons skilled in the art. When such bladder is applied, a reinforcement layer is not necessary.

As a rubber which constructs the bladder 51, rubbers such as butyl rubber, natural rubber, SBR, IR, BR, or EPDM, elastomers such as polyurethane, styrene, chloroethene, olefin, polyester, nitryl, or polyamide can be applied.

As a thread which constructs the thread-winding layer 52, threads made from nylon, polyester, or cotton are applied.

The peripheral edge 58 of each surface 56 of the foamed layer 53 (vulcanized rubber layer) which is divided to sectionalize the surface is formed in a shape of arc with the smooth seam on a virtual plane which penetrates into the center of a ball of the present Embodiment. The side face 59 of a partition 55 on the foamed layer 53 (vulcanized rubber layer) is formed, in order that virtual straight line on the side face 59 of the partition 55 on the foamed layer 53 (vulcanized rubber layer) approximately penetrates into the center of the ball. A skin layer 60 (for example, natural leather layer or synthetic leather layer) is attached on each surface of vulcanized rubber layer 53 which is divided to sectionalize the surface, but not limited to construction of the partition 55 described above. For example, a surface which slopes relative to the surface 56 which is divided to sectionalize the surface (for example, skin layer which has cross sectional trapezium) can be applied. The peripheral edge 58 of each surface 56 of the foamed layer 53 which is divided to sectionalize the surface is not necessarily formed in a shape of arc.

The partition 55 on the foamed layer 53 described above in a ball of the present Embodiment is obtained by vulcanizing in the state that unvulcanized rubber which has lower foamed property than the unvulcanized rubber is superposed on unvulcanized rubber with a foamed property described above. However, the method of making the partition 55 is not limited to such method. There is a mold M. which is provided with a cavity C. For example, in a cavity C, low (or few) foamed unvulcanized rubber is embedded in a mold M, and a body covered with thread wound around the body, which has high (or much) foamed unvulcanized rubber on the skin layer may be placed into a mold (not shown) to be vulcanized. However, it is not limited to such method, and the partition 55 can be also obtained by vulcanizing either unvulcanized partition 55 or unvulcanized surface 53 which is divided to sectionalize the surface. The partition 55 can be also obtained by joining with an adhesive agent even if both the partition 55 and surface 53 which is divided to sectionalize the surface are vulcanized. It is well known that methods for joining which are obvious to persons skilled in the art can be also applied

Referring to FIGS. 4(a) and 4(b), a method for producing the bladder 51, thread-winding layer 52, and vulcanized rubber layer 53 which construct a ball of the present Embodiment is explained.

Forming the bladder 51, thread-winding layer 52, and unvulcanized rubber layer 53.

After unvulcanized rubber 70 which has lower foamed property than the unvulcanized rubber layer 53 is superposed on the unvulcanized rubber layer 53, the layer is placed in the mold M to heat and pressurize only at predetermined time period (10 to 15 minutes) (at the temperature of 40 to 170° C., pressure 0 to 8 kgf/cm²).

The partition 55 on vulcanized rubber layer 53 can be obtained by opening mold M.

There is a tendency that when a particle diameter of foaming agent blended into rubber is reduced, foamed cell becomes to be fine in size, and when a particle diameter of foaming agent blended into rubber is enlarged, foamed cell becomes to be large in size.

As the amount of foamed cells, there is tendency that when the amount of foaming agents blended into rubber increases, the amount of foamed cells increases, and when the amount of foaming agents blended into rubber decreases, the amount of foamed cells decreases. There is also tendency that as the amount of foaming agents in vulcanized rubber layer 53 and that of partition 55 are approximated, the cells gradually decrease.

Embodiment 1

When the blending rate of a foaming agent in the unvulcanized rubber layer 53 of main portion (portions except for the partition 55) is 6.0 phr, the blending rate of foaming agent in the partition 55 is 4.0 phr, a particle diameter of foaming agent in main portion is under 20 μm, and a particle diameter of foaming agent in the partition 55 is under 10 μm, a foamed cell Ba with a size of 100 to 400 μm is obtained in a main portion, and a foamed cell Bb with a size of 50 to 100 μm is obtained in the partition 55 as shown in FIG. 5(a).

When the amount of a foaming agent is 4 to 6 phr, the partition 55 will include a large number of foamed cells Bb as shown in FIG. 5(a) A particle diameter of foaming agent is preferable to be under 10 μm to obtain reduced size of foamed cells.

Embodiment 2

When the blending rate of foaming agent in the unvulcanized rubber layer 53 of main portion (portions except for the partition 55) is 6.0 phr, the blending rate of foaming agent in the partition 55 is 3.0 phr (i.e. the amount of foaming agent is 1 to 4 phr in the partition 55), foamed state, in which the number of foamed cells in the partitions 55 (100 to 1000 pieces/cm²) is lower than that of foamed cells in the main portion (1000 to 10000 pieces/cm²) occurs as shown in FIG. 5(b). A diameter of a foamed cell in FIG. 5(b) is 100 to 400 μm.

A ball in the present invention is explained in detail with examples, but the present invention is not limited to the example.

EXAMPLE

The blending rate of rubber composition in each rubber, one is rubber used in the vulcanized rubber layer 53 which constructs a ball related to the example, the other is rubber used in the partition 55 was as shown in Table 3.

On the one hand, a ball related to U.S. Pat. No. 5,636,835 described above was used as a comparative example.

General standard, rebound, touch (softness), compressibility (hardness) and abrasion resistance were experimented. (refer to Table 1, Table 2 and FIG. 6) TABLE 1 Items to be estimated Example Comparative Example Materials of Natural leather Artificial leather: polyurethane skin layer Rebound Free Fall of 1.8 m under internal pressure of Free fall of 1.8 m under internal pressure of 0.7 kgf/cm² 0.7 kgf/cm² 129 cm 122 cm The sample was reluctant to bound as compared to example Touch Impact value of dropping the sample from Impact value of dropping the sample from (Softness) the point where a distance between the point the point where a distance between the point and the floor was 1 m under internal pressure and the floor was 1 m under internal pressure of 0.7 kgf/cm² of 0.7 kgf/cm² 91.35 kgf 92.94 kgf The sample was hard as compared to example Compressibility Compression energy in the case where the Compression energy in the case where the (hardness) sample was compressed by means of a jig having sample was compressed by means of a jig having a diameter of 10 mm with a compression of 5 kgf a diameter of 10 mm with a compression of 5 kgf 45.31 gf/cm 37.94 gf/cm The sample was hard as compared to example Abrasion Shooting test: 4000 times (comparison of Shooting test: 4000 times (comparison of resistance abrasion in a rib) abrasion In a rib) Internal pressure under 0.7 kgf/cm² · compression Internal pressure under 0.7 kgf/cm² · compression rate 81% rate 81% About rib: there was not generated a crack About rib: there was not generated a crack

TABLE 2 Rebound Example Free fall of 1.8 m The larger the 129 at 20° C. under internal numerical value Compara- pressure of 0.7 is, the better 122 tive kgf/cm² the sample Example bound (cm) Touch Example Impact test at The smaller 91.35 Compara- normal the numerical 92.94 tive temperature value is, the Example Free fall of 1 m softer the under internal sample is (kgf) pressure of 0.7 kgf/cm² Example Compression test The larger the 37.94 Compara- with hands numerical value 45.31 tive Compressibility of is, the softer Example being compressed the sample is under internal pressure of 0.7 kgf/cm²

TABLE 3 Blending rate Main Portion Partition Natural rubber 100.0 100.0 Calcium carbonate 25.0 25.0 Silica 10.0 10.0 Factice (trade mark) 5.0 5.0 Carbon black 7.0 7.0 Processing acid 3.5 3.5 Sulfur 2.4 2.4 Zinc oxide 5.0 5.0 Stearic acid 1.0 1.0 Accelerator 2.3 2.3 Foaming agent 6.0 3.0 Sum 167.2 164.2

It proves that as a result, a ball in the example and a ball in comparative example are equivalent about general standard and abrasion resistance as shown in FIG. 6, but the ball in the example is superior to a ball in the comparative example in rebound, touch (softness), and compressibility (hardness).

INDUSTRIAL APPLICABILITY

According to the present invention, a ball for ball game which has equal or increased cushioning property to a ball which has seams can be provided without providing inflatable raised seams with cushion layers under outer covering can be provided. 

1: A ball for ball game comprising: a bladder made of rubber or elastomer; and a foamed layer covering an outside of said bladder; wherein a skin layer is provided on each surface which is divided to sectionalize the surface of said foamed layer, and a partition on said foamed layer has lower foamed property than each surface which is divided to sectionalize the surface. 2: A ball for ball game comprising: a bladder made of rubber or elastomer; a reinforcement layer covering an outside of the bladder; and a foamed layer covering an outside of the reinforcement layer; wherein a peripheral edge of said each surface which is divided to sectionalize the surface of foamed layer is formed in a shape of arc with a smooth seam, a skin layer is provided on each surface which is divided to sectionalize the surface of said foamed layer, and a partition of said foamed layer has lower foamed property than each surface which is divided to sectionalize the surface. 3: The ball for ball game of claim 1, wherein the number of cells in a partition of said foamed layer is less than the number of cells in each surface which is divided to sectionalize the surface of said foamed layer. 4: The ball for ball games of claim 1, wherein the foamed property in partition of said foamed layer decreases gradually as an interval from each surface which is divided to sectionalize the surface increases. 5: The ball for ball game of claim 2, wherein the number of cells in a partition of said foamed layer is less than the number of cells in each surface which is divided to sectionalize the surface of said foamed layer. 6: The ball for ball games of claim 2, wherein the foamed property in partition of said foamed layer decreases gradually as an interval from each surface which is divided to sectionalize the surface increases. 7: The ball for ball games of claim 3, wherein the foamed property in partition of said foamed layer decreases gradually as an interval from each surface which is divided to sectionalize the surface increases. 8: The ball for ball games of claim 5, wherein the foamed property in partition of said foamed layer decreases gradually as an interval from each surface which is divided to sectionalize the surface increases. 